The present invention relates to a vehicle hinge, in particular for coupling a flap to a vehicle body, comprising a first link, a second link and a spring, wherein the first link and the second link are to be arranged pivotably in each case on a body of a vehicle and on a flap of a vehicle, and wherein, when the flap is closed, the spring pretensions the latter in the opening direction.
Single-joint hinges and multiple-joint hinges which have a spring as an opening aid are known from practice. For example, tail flaps which are acted upon by gas-filled compression springs are known, but these are afflicted with a series of drawbacks: the characteristic is severely temperature-dependent and, moreover, it is precisely in the closed position that the force of the gas-filled spring is often not sufficient to push open the flap.
Furthermore, for front flaps, compression springs which are arranged in the region of a hood lock and are released via a lever in the driver's cab are known from practice, but, because of a catch hook, they only lift the front flap for a short distance and then have to be released and guided further by hand.
German patent application DE 197 31 507 A1 describes a plurality of four-joint hinges which are in each case equipped with at least one supporting spring. A problem with all of these hinges is that the considerable opening force which is required for pushing open a tail flap and which, if appropriate, is applied by additional springs has to be overcome again by the user in the end phase of closing the flap, which considerably impairs the ease of operation. Furthermore, the flap is excessively accelerated particularly in the last third of its opening movement, for which reason considerable outlay has to be provided for an end stop.
German patent application DE 197 55 487 A1 describes a vehicle hinge, in which a flap is connected to a body via a four-joint arrangement, the flap being pretensioned in the opening direction with respect to the body under the force of a gas-filled compression spring, the gas-filled compression spring being arranged at its body-side end on an arrangement having a means of adjusting the direction of action in order to improve the poor opening behavior in the initial phase of the opening movement. An arrangement of this type is complicated to install and is costly and in fact entails costs of the same order of magnitude as an electric drive.
German patent application DE 197 21 941 A1 describes a vehicle hinge, in which the flap can be pivoted via a four-joint linkage comprising two links which are mounted pivotably on fastening parts for the flap and the body, where a leaf spring acts in the opening direction upon one of the links. A disadvantage of the known arrangement is that the spring force of the leaf spring has to be overcome by the user when closing the flap, thus limiting the ease of operation.
German Utility Model DE 202 01 316 U1 shows a vehicle hinge of the gooseneck type for a flap, including a gas-filled spring pivotably attached at a first end to the body of the vehicle for supporting the opening movement of the flap. The other end of the gas-filled spring is desplaceably and pivotably supported in a slot of a lever pivotably attached to the body. The lever is coupled to a rod being attached to the flap. The joint of the gas-filled spring changes its position within the slot of the lever depending upon the opening angle of the flap such that the distance to the joint axis of lever and body changes and accordingly induces different forces. This solution is expensive due to the number of parts necessary, and further, the sliding movement in a slot tends to induce noise and wear.
German Utility Model DE 201 08 874 U1 shows a hinge with an arrangement for supporting the opening movement of a part pivotable around one axis, wherein the prestress of a driving spring in a first step urges the pivotable part in an open position. For closing the pivotable part, the drive spring is nearly completely stressed in a first closing movement phase and in a subsequent closing movement phase, the driving spring does nearby not need to be overcome. For this purpose, a pin is guided in an approximately triangular slot, wherein the pin is guided one edge of the triangle in the opening movement and along the two other edges of the triangle in the closing movement.
German patent application DE 198 46 600 A1 shows a four-joint hinge for a flap, wherein the opening movement driven by a gas-filled spring is initially supported by a leaf spring, wherein the leaf spring is arranges on an attachment part assigned to the body of a vehicle and abuts against a roller provided on the attachment part assigned to the flap. Only a brief impulsion for opening is possible, and the force of the leaf spring has to be overcome by tensioning it with closing the flap.
German patent application DE 101 17 796 A1 shows a four-joint hinge for a flap, wherein the opening movement driven by a gas-filled spring is initially supported by a leaf spring formed as a V, wherein a first leg of the leaf spring is arranged on a link of the four-joint hinge and another leg of the leaf spring abuts against an attachment part of the four-joint hinge assigned to the flap. Here too, the the leaf spring has to be tensioned with closing the flap.
German patent application DE 100 01 054 A1 shows a flap drive, wherein the force for driving the flap is generated by a motor, wherein the motor is supported by a first spring and a second spring, these two springs being tensioned by the motor again when the flap is being closed.